Question

已知5a-3a+1的值为5,求代数式4a^2-6a+8的值

Answer 1

5a-3a+1=5
2a=4
a=2
4a^2-6a+8
=3x2^2-6x2+8
=12-12+8
=8

Answer 2

5a-3a+1=5: 5-1=4 5a-3a=2a, 那么2a=4
所以：4a的平方-6a+8
=3x2的平方-6x2+8
=12-12+8
=8
祝你学习进步！